Ore beneficiation process and agent



Patented Apr. 14, 1964 3,129,166 (BRE BENEFICIATION PRUCESS AND AGENT Marvin B. Giliis, Glenview, Iii, assignor to International Minerals & Chemical Corporation, a corporation of New York No Drawing. Filed June 30, 1961, Ser. No. 120,916 13 Claims. (Cl. 209166) The present invention relates to the beneficiation or concentration of ores. In one of its aspects, the present invention relates to a method for the concentration of phosphate minerals by froth flotation. In a more specific aspect the present invention relates to a froth flotation process effective, inter alia, to separate silica from phos phate minerals. In another of its aspects, this invention relates to a reagent effective in the concentration and beneficiation of ores.

Phosphate rock is an ore which is a crude phosphatic material or mineral consisting of more or less impure noncrystalline calcium fluorphosphate. Phosphate rock occurs widely in nature and normally is in association with silica as a major gangue constituent. In addition to the silica, other gangue constituents present include silicates, calcium carbonate, carbonaceous material, heavy minerals, and the like, all of which contain no phosphorus and are of little, if any, nutritive value so far as plants and animals are directly concerned.

Many methods have been devised in the past for treating such ores to effect beneficiation or concentration of the phosphatic constituents by removing the siliceous, carbonaceous and heavy minerals portions therefrom. Several methods involve the desliming, dewatering and separation of either pulped or unpulped material in order to effect this beneficiation and concentration. One commonly used method involves the reagentizing and froth flotation of an aqueous pulp of the ore with an anionic collecting agent used in conjunction with a relatively highboiling hydrocarbon oil, together with the use of a basic component such as a caustic (NaOH). When an aqueous suspension or pulp of phosphate rock is reagentized with a composition containing this combination, and the same agitated and aerated in an aqueous suspension and flotation cell, the phosphatic values of the rock are found to rise and become segregated in the upper portion of the suspension while the siliceous values tend to settle or deposit in the lower portion of the suspension. The beneficiated or enriched phosphatic material, which is Withdrawn from the upper portion of the flotation cell, is usually collected as rougher concentrate. The rougher concentrate normally contains from about 8% to about 20% by weight of silica. The rougher concentrate can be, and usually is, further beneficiated in a subsequent froth flotation process, generally employing a cationic agent such as long chain fatty primary amines and their acid salts.

Various methods of operating beneficiation and concentration processes of the flotation type to improve the recovery and the grade of the phosphate in the beneficiated product have been used in the past. Some of the factors which affect the recovery and the grade of the phosphate flotation product are the properties of the ore, the pH of the slurry, the type and quantity of reagents and the type and quantity of aeration. Because of the large scale character of the business of producing phosphate rock concentrates, and the highly competitive market existing in such business, it is important that the reagentizing composition be relatively inexpensive. Great effort has been expended to discover collecting agents which will be more efficacious or which cost less to use than those reagents heretofore employed. It is, however, not alone desirable to empioy a less expensive collector or a collector which may be used in smaller quantities to effect an efficient segregation of the phosphatic values. It is also important that the concentrate recovered be of relatively high purity; that is, relatively free of solids other than the desired phosphatic material.

Stated differently, it is a continuing object of research in ore beneficiation and concentration processes to upgrade the quality of ore concentrates, preferably at equal or lower economic costs. Considerable work has been, and continues to be, done toward the discovery of effective variations in processing steps and equipment. The present invention, however, in its major aspect is directed toward a more eflicient and economic reagent for use in ore concentration and beneficiation processes, and comprises a particular mixture of cationic reagents having synergistic properties.

It is, therefore, an object of the present invention to provide a method for the beneficiation or concentration of ores.

It is another object of the present invention to provide a method for the concentration of phosphate minerals by froth flotation.

It is still another object of the present invention to provide a froth flotation process to separate silica from phosphatic ores.

A further object of the present invention is to provide a reagent effective in the concentration and the beneficiation of ores.

Additional objects and advantages of the present invention will become apparent from the description which follows.

As mentioned earlier herein, a conventional procedure in the beneficiation and concentration of phosphate ores is to first subject the raw ore to a flotation process involving the use of an anionic agent such as fatty acids and fatty acid soaps, either alone or in admixture with hydrocarbon materials such as kerosene or crude oil, in order to produce What is known as a rougher concentrate. This rougher concentrate is then subjected to a second beneficiation step in which a cationic agent such as long chain primary fatty amines and/ or their acid salts are used as the essential flotation reagent to effect a further upgrading of the ore material to separate silica and other acid insolubles present therein. Conventional agents which have been used for this purpose in the past, in addition to those mentioned above, include primary rosin amines, primary tall oil amines, mixed crude primary amines and water soluble or dispersible acid salts of the foregoing.

In accordance with the present invention, I have discovered that improved results are obtained in ore concentration processes if there is employed therein a reagent comprising a mixture of reagents containing from about 0.25 to preferably from 0.5 to 1 weight proportions of (A) a conventional amine reagent per weight proportion of (B) the reagent produced by reacting about one mole equivalent of a polyalkylene amine having the formula in which n, m and x are whole numbers with from about 1.8 to about 2.2 mole equivalents, preferably about 2.0, of a fatty acid as triglyceride at a temperature of about to about 210 for a period of about A to about 2 hours in the presence of about 0.1 to about 0.5 weight percent of caustic, basis triglyceride, and acid salts of the above two reagents. I have discovered that the reagent of the present invention produces a synergistic result in that in the proportions recited the combination, at similar rates of use, produces a concentrate having a smaller proportion of acid insolubles therein than either of the two reagents used at the same rate. Stated alternatively, to achieve any given percentage of acid insolubles in an ore concentrate a lesser total quantity of the mixture of reagents of the present invention can be used than if either of the two reagents are used individually. Concomitant to this benefit is the factor of a considerable reduction in the costs required to achieve an ore concentrate of a selected grade.

As used in the specification, the term conventional amine reagent includes long chain primary fatty amines having from about 12 to 22 carbon atoms in the fat moiety, preferably 16 to 18 carbon atoms, as are derived by the ammoniation, dehydration, and hydrogenation of fatty acids contained, as glycerides, in soybean oil, cottonseed oil, tallow, coconut oil, marine oils, etc.; primary rosin amines, primary tall oil amines, mixed crude primary amines which may be still bottoms resulting from the fractionation and/or distillation of amines produced as described hereinbefore, and water-soluble or dispersible acid salts of the foregoing, such as the hydrochloride and acetate. The above materials can be used as mixtures or individually and as totally or partially neutralized water-soluble or dispersible acid salts.

The reagent used in combination with the conventional amine flotation reagent as described hereinabove is the material produced by reacting about one mole equivalent of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 mole equivalents of a fatty acid as triglyceride at a temperature of about 190 to about 210 C. for a period of about /1 to about 2 hours in the presence of about 0.1 to about 0.5 weight percent, basis triglyceride, caustic, and acid salts of said materials. Typical polyalkylene polyamines which can be used in the preparation of these materials include diethylene triamine, dipropylene triamine, dibutylene triamine, triethylene triamine, tetraethylene pentarnine or mixtures of any two or more of such polyamines, either as relatively pure compounds or crude mixtures. In general, they are polyamines the different amino groups of which are separated from one another by a hydrocarbon radical containing from 2 to 12 carbon atoms. Although it is possible that relatively crude mixtures of the various polyamines can be used for reacting with the fatty acid triglycerides, the preferred polyamine is diethylene triamine. The fatty acid triglyceride used to prepare the materials described are found in the fats and oils of either vegetable or animal origin, such as those contained in coconut oil, palm oil, palm kernel oil, cottonseed oil, corn oil, linseed oil, olive oil, peanut oil, fish oils, tallow, and hog fat or lard oils. Because of its low price, and also in view of the predominance of C-18 aliphatic chains, hog fat is the preferred triglyceride employed.

In preparing the materials used in the combination, about 1 mole equivalent of the polyalkylene polyamine is mixed with from about 1.8 to about 2.2 mole equivalents, preferably about 2.0 mole equivalents of the fatty acid as triglyceride and the mixture is maintained at a temperature of about 190 to about 210 C., with agitation, for a period of about A to about 2 hours. About 0.25 weight percent of caustic, basis triglyceride, is mixed with the polyamine and triglyceride prior to heating, although it can be mixed after the temperature has been reached. Using the shorter heating periods, viz., one hour or below, it is a preferred practice to quench the reaction mixture to about 100 C. I have found that this procedure produces a material which is comparable in its flotation effects to those materials produced after prolonged heating. It is also to be noted that materials produced employing the preferred mole ratio of polyamine and triglyceride contain about 8-10 weight percent of monoglycerides which contributes to their efficiency as flotation reagents.

When the material is produced from fatty acid triglycerides the average molecular weight of the fatty acids of which is relatively high, such as those of hog fat, the

material can be used in the form of a free base. The same is, in general, true of the conventional amine ingredient. Therefore, it is not necessary in the present invention to use water-soluble acid salts, and compounds in the form of the free base can be used, provided satisfactory dispersion and distribution is effected. There may, however, be economic benefit to using neutralized materials (acid salts). In froth flotation operations, dispersion can be effected by feeding an alcohol solution of the combined reagent into the flotation circuit, or by the use of emulsions containing the reagents dispersed therein.

The reagents of the present invention are elfective promoters or collecting agents for acidic materials generally, and such acid materials may be worthless gangue or valuable ore constituents. The most important use, however, is in connection with the froth flotation of silica from non-metallic ores in which the siliceous material represents a much smaller proportion of the ore rather than metallic and sulfide ores in which the gangue usually represents the major proportion of the ore. Representative acidic ore materials are the feldspars, quartz, pyroxenes, spinels, biotite, muscovite, clays, and the like.

While as stated heretofore, the present invention is not limited to the treatment of any particular ore materials, it has been found to be well suited for froth flotation of silica from phosphate rock, and this is a preferred embodiment of the invention. In the processes of removing silica from phosphate rock, the conditions are such that particularly complete removal of the silica must be accomplished in order to produce a saleable phosphate material. It is, therefore, an advantage of this invention that the reagents of the present invention not only effect satisfactory removal of the silica but are economic in the amounts used. The total quantities of the inventive combination of reagents required range from about 0.1 to about 1.0 pound per ton of ore, depending upon the particular ore and the particular reagent. The invention is not, however, limited to the use of such quantities.

The reagents of the present invention can be used alone or in admixture with other promotors, cooperating materials such as conditioning agents, activators, frothing agents, dispersing agents, oily materials such as hydrocarbon oils, and the like.

The reagents of the present invention are also adaptable for use in any of the ordinary concentrating processes, such as film flotation, tabling, and particularly in froth flotations. The ore concentrating processes employed will depend upon the particular type ore which is being processed; for example, in connection with phosphate rock, relatively coarse phosphate bearing material, for example 28 mesh or larger, can be economically concentrated by using these reagents in conjunction with other materials such as fuel oil or pine oil and subjecting to concentration by the use of tables or by film flotation. The 28 mesh phosphate rock material is best concentrated by means of froth flotation employing the improved reagents of the present invention.

When the reagent of the present invention is employed as promotor in the froth flotation of silica from phosphate rock, the conditions may be varied in accordance with procedures known to those skilled in the art. The reagents can be employed in the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents such as alcohol and the like. The reagents can be introduced into the ore pulp in the flotation cell without prior conditioning, or they can be conditioned with the ore pulp prior to the actual concentration operation. They can also be stage-fed into the flotation circuit.

The following examples are intended to illustrate the underlying principles of the present invention and are not to be construed as unduly limiting thereof.

EXAMPLE I A series of runs was conducted under substantially the same standard conditions of treatment and involved the same amounts of ore and, except as indicated, all conditions, reagents, and treatments remained constant so that strictly comparable results were obtained.

In each instance, Florida phosphate rock of about 28 +150 mesh, which had been previously subjected to an anionic float, and which contained from about 8 to about 20% by weight of silica was used as the feed material. The feed was reagentized, as will be described more fully hereinafter, and passed to a flotation cell of conventional type with the various types of reagents in the amounts specified below. Each amine was 50% neutralized with acetic acid and used as a 2.5% by weight water emulsion. Kerosene was also added to the emulsion in the amount of two parts kerosene to one part amine by weight. The flotation operation was made at a pH of about 7.4.

Amine (A) was a 5050 weight percent mixture of primary tallow amine acetate and primary rosin amine. Materials of this character are available commercially under the tradename Armac T and Rosin D, and are well known commercial amine flotation reagents. Amine (B) was a reagent prepared by reacting one molar proportion of diethylene triamine, with about 2 molar proportions of fatty acid in the form of hog fat triglycerides at a temperature of about 200 C. for a period of about 1 hour in the presence of about 0.25 weight percent of sodium hydroxide, basis triglyceride, followed by quenching to a temperature of about 100 C. Amine (C) was a mixture consisting of one part by weight of amine (A) and two parts by weight of amine (B). Amine (D) was a mixture consisting of one part by weight of amine (A) and one part by weight of amine (B). The results of the runs are summarized in Table 1 below.

Table 1 Grade of Gene. Reeoveryin Concen- Amine Grade of trate Amine Rate, lbsl- Tails,

Used ton Feed Percent Percent Percent BPL Acid BPL Wt. Percent Insol. percent BPL It will be seen from the data summarized that when 0 EXAMPLE II In this example, a series of runs were conducted, except as noted in the data presented, in the same fashion and under the same conditions as described in Example I. HoweverQthe data are presented in a different fashion to illustrate the improved economics of employing the pres ent reagents. In the table the levelsof reagent usage and the costs incurred for the reagent required to produce an ore concentrate of a specified percentage of acid insolubles are tabularized.

Amine (A) was a 50-50weight percent mixture of primary tallow amine acetate and primary rosin amine. Materials of this character are available commercially under the tradenames Armac T and Rosin D and are well known commercial amine flotation reagents. It will be noted that this mixture is comparable to a 50-50 weight percent mixture of primary tallow amine and primary rosin amine 50% neutralized with acetic acid.

- the materials.

Amine (B) is the same'amine (B) described in Example I. Amine (E) is a 50-50 weight percent mixture of amine (B) and a blend of mixed crude primary amines (Lot No. 8881) 50% neutralized with acetic acid. These mixed crude amines are, in general, still bottoms resulting from the fractionation and/or distillation of primary fatty amines, which are sold in a more refined and pure form. Materials of this character are available commercially from manufacturers of primary fatty amines. Amine (F) is a 50-50 weight percent mixture of amine (B) and a blend of mixed crude amines (Lot No. 8650) 50% neutralized with acetic acid. Amine '(G) is a 50-50 weight percent mixture of amine (B) and Hercules Delamine 80, 50% neutralized with acetic acid. Hercules Delamine is a blend of C fatty primary aliphatic amines, mostlystearyl and oleyl. Amine (H) is a 5 0-50 weight percent mixture of Hencules Delamine 80 and a blend of mixed crude amines (Lot No. 8395) 40% neutralized with acetic acid.

In the cost factor column in the data presented, the calculations are made on a basis of then current prices for Amine (B), although not available commercially, was priced at about 16.5 cents per pound on the basis of engineering cost estimates.

The results are set forth inTable 2 below.

Table 2 At 4.0% Insolubles Consumption Delivered Amine Percent Cost/ton oi Feed BPL of Lb .lton Percent Tails Feed Dollar Percent Amine A 0.189 100.0 5. 40 0.056209 100.0 Amine B-% neutralized 0. 285 150. 8 5. 90 0. 046821 83. 3 Amine Br-75% neutralized 0.325 172.0 6. 53 0. 053442 95. 1 Amine B-50% At 2.5% Insolubles At 2.25% Iusolubles Amine A 0. 254 100. 0 8. 30 0. 075540 100.0 Amine B50% neutralized 0. 256 100. 8 14. 60 0.042139 55. 8 Amine E 0. 126 40. 6 16. 00 0. 024908 33. 0 Amine G 0. 114 44. 9 16. 90 '0. 021278 28. 2

exemplified in terms of its preferred embodiments, those skilled in the art will readily appreciate that variations can be made without departing from the sphere and scope of the invention.

I claim:

1. In an ore concentration process for separating acidic ore materials from other ore constituents, the step which comprises carrying out the concentration operation in the presence of a reagent selected from the group consisting of I a mixture of reagents containing from about 0.25 to about 3 weight proportions of (A) a conventional amine flotation reagent per weight proportion of (B) the reagent produced by reacting about 1 mole of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 mole equivalents of a fatty acid triglyceride at a temperature of about 190 to about 210 C. for a period of about A to about 2 hours in the presence of about 0.1 to about 0.5 weight percent caustic, basis triglyceride; II partially neutralized I; and III totally neutralized I.

2. In a froth flotation process for separating non-metallic ore values from acidic ore constituents, the step which comprises subjecting the ore to froth flotation in the presence of a reagent selected from the group consisting of I a mixture of reagents containing from about 0.5 to about 1 weight proportion of (A) a conventional amine flotation reagent per weight proportion of (B) the reagent produced by reacting about 1 mole of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 mole equivalents of a fatty acid triglyceride at a temperature of about 190 to about 210 C. for a period of about 1 hour in the presence of about 0.25 weight percent caustic, basis triglyceride, followed by quenching to about 100 C.; II partially neutralized I; and III totally neutralized I.

3. In a froth flotation process for separating phosphate ore values from acidic siliceous gangue, the step which comprises subjecting the ore to froth flotation in the presence of a reagent selected from the group consisting of I a mixture of reagents containing from about 0.25 to about 3 weight proportions of (A) a conventional amine flotation reagent per weight proportion of (B) the reagent produced by reacting about 1 mole of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 mole equivalents of a fatty acid triglyceride at a temperature of about 190 to about 210 C. for a period of about A to about 2 hours in the presence of about 0.1 to about 0.5 weight percent caustic, basis triglyceride; -II partially neutralized I; and III totally neutralized I.

4. In a froth flotation process for separating phosphatic ore values from acidic siliceous gangue, the step which comprises subjecting the ore to froth flotation in the presence of a reagent selected from the group consisting of I a mixture of reagents containing from about 0.25 to about 3 weight proportions of a first mixture (A) containing from about 100 to about 50 weight percent of primary tallow amine and the remainder primary rosin amine, per weight proportion of (B) the reagent produced by reacting about 1 mole of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 mole equivalents of a fatty acid triglyceride at a temperature of about 190 to about 210 C. for a period of about M1 to about 2 hours in the presence of about 0.1 to about 0.5 weight percent caustic,

8 basis triglyceride; II partially neutralized I; and III totally neutralized I.

5. In a froth flotation process for separating phosphate ore values from acidic siliceous gangue, the step which comprises subjecting the ore to froth flotation in the presence of a reagent selected from the group consisting of I a mixture of reagents containing from about 0.5 to about 1 weight proportion of (A) a first mixture containing about 50 weight percent primary tallow amine and about 50 percent primary rosin amine per weight proportion of (B) a reagent produced by reacting about 1 mole of diethylene triamine with 2 mole equivalents of an animal fat triglyceride at a temperature of about 200 C. for a period of about 1 hour in the presence of about 0.25 weight percent sodium hydroxide followed by quenching to about C.; II partially neutralized I; and III totally neutralized I.

6. A process according to claim 3 wherein from about 0.1 to about 1 pound of reagent are employed per ton of ore treated.

7; A process according to claim 4 wherein the acetic acid salts of (A) and (B) are employed.

8. A process according to claim 5 wherein (A) and (B) are neutralized with acetic acid to between about 50 and about 100 percent neutralization.

9. An ore flotation reagent selected from the group consisting of I a mixture of reagents consisting essentially of from about 0.25 to about 3 weight proportions of (A) a conventional amine flotation reagent per weight proportion of (B) a reagent produced by reacting about 1 mole of a polyalkylene polyamine having the formula in which n, m, and x are whole numbers with from about 1.8 to about 2.2 moleequivalents of a fatty acid triglyceride at a temperature of about to about 210 C. for a period of' about A to about 2 hours in the presence of about 0.1 to about 0.5 weight percent caustic, basis triglyceride; II partially neutralized I; and III totally neutralized I.

10. An ore flotation reagent according to claim 9 containing between about 0.5 and about 1 weight proportion of (A) per weight proportion of (B).

11. An ore flotation reagent according to claim 9 wherein said polyalkylene polyamine is diethylene triamine.

12. An ore flotation reagent from the group consisting of I a mixture of reagents consisting essentially of from about 0.25 to about 3 weight proportions of (A) a first mixture containing about 50 weight percent primary tallow amine and about 50 weight percent primary rosin amine, per weight proportion of (B) a reagent produced by reacting about 1 mole of diethylene triamine with 2 mole equivalents of hog fat triglyceride at a temperature of about 200 C. for a period of about 1 hour in the presence of about 0.25 weight percent sodium hydroxide, basis triglyceride, followed by quenching to about 100 C.; II partially neutralized I; and III totally neutralized I.

13. An ore flotation reagent according to claim 12 containing between about 0.5 and about 1 weight proportion of (A) per weight proportion of (B).

References Cited in the file of this patent UNITED STATES PATENTS 2,278,060 Christmann Mar. 31, 1942 2,298,281 Corley Oct. 13, 1942 2,321,186 Christmann June 8, 1943 2,844,609 Tesoro July 22, 1958 2,883,277 Belswanger Apr. 21, 1959 2,914,174 Haseman Nov. 24, 1959 3,009,575 Keen et a1. Nov. 21, 1961 

1. IN AN-ORE CONCENTRATION PROCESS FOR SEPARATING ACIDIC ORE MATERIALS FROM OTHER ORE CONSTITUENTS, THE STEP WHICH COMPRISES CARRYING OUT THE CONCENTRATION OPERATION IN THE PRESENCE OF A REAGENT SELECTED FROM THE GROUP CONSISTING OF 1 A MIXTURE OF REAGENTS CONTAINING FROM ABOUT 0.25 TO ABOUT 3 WEIGHT PROPORTIONS OF (A) A CONVENTIONAL AMINE FLOTATION REAGENT PER WEIGHT PROPORTION OF (B) THE REAGENT PRODUCED BY REACTING ABOUT 1 MOLE OF A POLYALKYLENE POLYAMINE HAVING THE FORMULA 